Aircraft engines are typically housed in a nacelle. A pylon extends from the nacelle to couple the engine to the aircraft. As one example, the pylon may couple the engine to a wing of the aircraft (e.g., the engine may be suspended below the wing). As another example, the pylon may couple the engine directly to the fuselage of the aircraft (e.g., the engine may be mounted to the side of the fuselage proximate the rear of the fuselage).
In modern aircraft, various steps are typically taken to inhibit the spread of flames from the engine to the wings and fuselage of the aircraft. For example, all structural interfaces within the engine/pylon assembly are typically sealed with fireproof (or fire-resistant) material to eliminate gaps through which flames may propagate.
The structural interfaces of an aircraft vary with manufacturing tolerances and many structural interfaces are dynamic, thereby rendering many structural interfaces of an aircraft difficult to seal. For example, the interface between the pylon fairing and the nozzle of the aircraft engine can be quite dynamic as a result of significant temperature fluctuations. Rubber seals, such as silicone rubber seals, have been used to seal structural interfaces in aircraft, but high operating temperatures limit the use of rubber seals. Metallic feather seals have been used to seal structural interfaces that are too hot for rubber seals. However, metallic feather seals are difficult to install, present durability issues that increase maintenance costs, and typically must be manufactured using relatively high-cost techniques, such as hydroforming.
Accordingly, those skilled in the art continue with research and development efforts in the field of aircraft fire seals.